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• A nanoplatform with oxygen self-supplying and heat-sensitizing capabilities is prepared using a simple and cost-effective method. • The nanoplatform can generate oxygen in response to the acidic microenvironment of the biofilm to alleviate its hypoxic state. • Under near-infrared irradiation, the nanoplatform converts oxygen into a significant amount of singlet oxygen and heat to eradicate biofilm. • The nanoplatform remarkably enhances the efficiency of photodynamic therapy in eradicating multidrug-resistant biofilms. Bacterial biofilms, especially those caused by multidrug-resistant bacteria, have emerged as one of the greatest dangers to global public health. The acceleration of antimicrobial resistance to conventional antibiotics and the severe lack of new drugs necessitates the development of novel agents for biofilm eradication. Photodynamic therapy (PDT) is a promising non-antibiotic method for treating bacterial infections. However, its application in biofilm eradication is hampered by the hypoxic microenvironment of biofilms and the physical protection of extracellular polymeric substances. In this study, we develop a composite nanoplatform with oxygen (O 2) self-supplying and heat-sensitizing capabilities to improve the PDT efficacy against biofilms. CaO 2 /ICG@PDA nanoparticles (CIP NPs) are fabricated by combining calcium peroxide (CaO 2) with the photosensitizer indocyanine green (ICG) via electrostatic interactions, followed by coating with polydopamine (PDA). The CIP NPs can gradually generate O 2 in response to the acidic microenvironment of the biofilm, thereby alleviating its hypoxic state. Under near-infrared (NIR) irradiation, the nanoplatform converts O 2 into a significant amount of singlet oxygen (1O 2) and heat to eradicate biofilm. The generated heat enhances the release of O 2 , accelerates the generation of 1O 2 in PDT, increases cell membrane permeability, and increases bacterial sensitivity to 1O 2. This nanoplatform significantly improves the efficacy of PDT in eradicating biofilm-dwelling bacteria without fostering drug resistance. Experiments on biofilm eradication demonstrate that this nanoplatform can eradicate over 99.9999% of methicillin-resistant Staphylococcus aureus (MRSA) biofilms under 5-min NIR irradiation. Notably, these integrated advantages enable the system to promote the healing of MRSA biofilm-infected wounds with negligible toxicity in vivo, indicating great promise for overcoming the obstacles associated with bacterial biofilm eradication. [Display omitted] [ABSTRACT FROM AUTHOR]

• An injectable decellularized extracellular matrix hydrogel is developed to deliver exosomes encapsulating curcumin locally to the infarcted area of the heart. • The solubility and bioavailability of curcumin are enhanced by exosomal encapsulation, and the hydrogel improves the retention of exosomes. • Intramyocardial injection of this hydrogel promotes angiogenesis, decreases collagen deposition, and prevents cardiac fibrosis to facilitate cardiac repair after myocardial infarction. Excessive cardiac fibrosis impairs cardiac repair after myocardial infarction (MI). In this work, an injectable composite hydrogel integrating natural biomaterials, exosomes, and bioactive molecules is developed to prevent or alleviate cardiac fibrosis. Curcumin, a natural molecule with antifibrotic activity, is encapsulated in the exosomes that are isolated from bone marrow-derived mesenchymal stem cells to enhance its water solubility and bioavailability. These composite exosomes are efficiently internalised by fibroblasts and effectively inhibit their transition to myofibroblasts in vitro. Decellularized porcine cardiac extracellular matrix (dECM) hydrogel is used as the carrier for delivering these composite exosomes to the infarcted myocardium, not only improving the retention of exosomes but also providing mechanical support and structural protection. Injection of this hydrogel into the infarcted heart of a mouse MI model leads to a decrease in collagen deposition, alleviation of fibrosis, a reduction in infarct size, and an improvement in cardiac function. The reported composite hydrogel comprising natural materials and biomolecules exhibits good biocompatibility and bioactivity. Altogether, this study demonstrates that the dECM hydrogel is a suitable platform for the local delivery of antifibrotic biomolecule-encapsulating exosomes to prevent myocardial fibrosis after MI and have great potential for the treatment of MI in clinical settings. [Display omitted] [ABSTRACT FROM AUTHOR]

• A multifunctional dressing based on bacterial cellulose deposited with a tannic acid/Cu2+ ion/Mg2+ ion complex film (BTCM) is developed. • The BTCM membrane can effectively eradicate bacteria in the wound area under a short-term near-infrared irradiation. • The BTCM membrane can promote proliferation, migration, and tube formation of endothelial cells in vitro and angiogenesis in vivo. • The BTCM membrane can accelerate the healing process of the bacteria-infected full-thickness skin wounds. For most traditional wound dressings, it is challenging to simultaneously eliminate bacteria and promote angiogenesis to accelerate the healing process of bacteria-infected wounds. In this work, we develop a multifunctional dressing based on bacterial cellulose (BC) deposited with a tannic acid/Cu2+ ion/Mg2+ ion (TCM) complex film. Overall, the TCM complex exhibits robust interfacial adhesion to modify BC and good photothermal properties to effectively eradicate bacteria in the wound area under near-infrared (NIR) irradiation. The individual components of the TCM complex have several advantageous features for wound healing, such as antibacterial ability and negligible cytotoxicity; in particular, the released Cu2+ and Mg2+ ions are favorable for the proliferation, migration, and tube formation of endothelial cells in vitro. The results of in vivo experiments demonstrated that with the assistance of NIR irradiation, this composite dressing is more effective than traditional gauze or pristine BC dressing in promotion of angiogenesis and collagen deposition without causing remarkable inflammation, thereby accelerating the healing process of bacteria-infected full-thickness skin wounds. This work thus provides a simple and facile way to fabricate multifunctional BC-based dressings that could be potentially used for treating infected wounds. [Display omitted] [ABSTRACT FROM AUTHOR]

• A nanoplatform equipped with "disruption and killing" functions is designed to enhance the effectiveness of conventional antibiotics for biofilm eradication. • The nanoplatform can degrade the polysaccharides of extracellular polymeric substances to disrupt the structural integrity of biofilms. • Under near-infrared irradiation, the nanoplatform facilitates the release and the bacterial uptake of rifampicin to effectively eliminate the bacteria within biofilms. Due to the absence of timely and effective therapies, infections induced by bacterial biofilms have been widely acknowledged as a significant global public health concern. In modern times, aside from surgical intervention (when appropriate), antibiotics are the sole clinical option for treating biofilm-associated infections. However, the rise of drug resistance, as well as the poor therapeutic effects of current treatment regimens in eliminating biofilms highlight the requirement for novel strategies to enhance the accessibility of antibiotics in the "post-antibiotic era". The current study presents a multifunctional nanoplatform equipped with a "disruption and killing" function to enhance the effectiveness of conventional antibiotics for the eradication of biofilms. Herein, mesoporous silica nanoparticles were employed as carriers to encapsulate the model antibiotic rifampicin (Rif). Subsequently, the nanoparticles were coated with layers of the tannic acid/iron ion (TA/Fe) complex and immobilized with α-amylase. The α-amylase present in the outer layer can degrade the polysaccharides of extracellular polymeric substances (EPS), which in turn disrupts the structural integrity of the biofilms, thus facilitating the entry of the nanoplatform. When exposed to near-infrared (NIR) light, the TA/Fe complex layers can generate heat, which facilitates the release of Rif and increases the bacterial uptake of Rif by damaging the bacterial cell membrane, ultimately resulting in the elimination of bacteria within biofilms. The in vitro experiments demonstrated that this nanoplatform effectively eliminated over 99% of biofilms formed by Staphylococcus aureus and Pseudomonas aeruginosa when exposed to NIR radiation for 10 min. Additionally, in vivo experimental findings further validated the extensive therapeutic efficacy of this nanoplatform against biofilm-infected wounds, accelerating the rate of healing and reducing inflammatory reactions. To summarize, this nanoplatform provides a novel avenue to improve the effectiveness of conventional antibiotics in eradicating bacterial biofilms. [Display omitted] [ABSTRACT FROM AUTHOR]